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Endothelins have been reported to exert a wide range of electrophysiological effects in mammalian cardiac cells. These results are controversial and human data are not available. Our aim was to study the effects of endothelin-1 (ET-1, 8 nmol/l) on the L-type calcium current (I Ca-L) and various potassium currents (rapid component of the delayed rectifier, I(More)
The sodium-calcium exchanger (NCX) was considered to play an important role in arrhythmogenesis under certain conditions such as heart failure or calcium overload. In the present study, the effect of SEA-0400, a selective inhibitor of the NCX, was investigated on early and delayed afterdepolarizations in canine ventricular papillary muscles and Purkinje(More)
The aim of the present work was to study the profile of the rapid delayed rectifier potassium current (I Kr) and the inward rectifier potassium current (I K1) during ventricular repolarization as a function of action potential duration and rate of repolarization. Whole cell configuration of the patch clamp technique was used to monitor I Kr and I K1 during(More)
AIM The aim of the present study was to give a parametric description of the most important K(+) currents flowing during canine ventricular action potential. METHODS Inward rectifier K(+) current (I(K1)), rapid delayed rectifier K(+) current (I(Kr)), and transient outward K(+) current (I(to)) were dissected under action potential clamp conditions using(More)
SEA0400 and KB-R7943 are compounds synthesised to block transsarcolemmal Na+/Ca2+ exchange current (INa/Ca); however, they Have also been shown to inhibit L-type Ca2+ current (ICa). The potential value of these compounds depends critically on their relative selectivity for INa/Ca over ICa. In the present work, therefore, the concentration-dependent effects(More)
The effect of action potential duration and elevated cytosolic sodium concentration on the forcefrequency relationship in isolated rabbit, guinea pig and rat papillary muscle preparations was studied. Shortening of action potential duration in guinea pig and rabbit from 150–200 ms to values characteristic of rat (20–40 ms), using the K(ATP) channel(More)
OBJECTIVES The aim of the present study was to compare the apico-basal distribution of ion currents and the underlying ion channel proteins in canine and human ventricular myocardium. METHODS Ion currents and action potentials were recorded in canine cardiomyocytes, isolated from both apical and basal regions of the heart, using whole-cell voltage clamp(More)
Fluoxetine is a widely used antidepressant compound having selective serotonin reuptake inhibitor properties. In this study, the actions of fluoxetine were analyzed in guinea pig, rat, rabbit and canine ventricular myocardiac preparations using conventional microelectrode and whole cell voltage clamp techniques. Low concentrations of fluoxetine (1–10(More)
Distinct differences exist in action potentials and ionic currents between rabbit, rat, and guinea pig ventricular myocytes. Data obtained at room temperature indicate that about half of the rabbit myocytes show prominent phase 1 repolarization and transient outward current. Action potentials in guinea pig ventricular myocytes resemble those from rabbit(More)
BACKGROUND AND PURPOSE While the slow delayed rectifier K(+) current (I(Ks)) is known to be enhanced by the stimulation of β-adrenoceptors in several mammalian species, phosphorylation-dependent regulation of the rapid delayed rectifier K(+) current (I(Kr)) is controversial. EXPERIMENTAL APPROACH In the present study, therefore, the effect of isoprenaline(More)